I had issue also gconf-sanity-check-2 exited with status 256
problem was wrong /tmp directory permissions (for some reason wasn't drwxrwxrwxt and owner wasn't root.root)
I had issue also check-2 exited with status 256
gconf-sanity-
problem was wrong /tmp directory permissions (for some reason wasn't drwxrwxrwxt and owner wasn't root.root)